if (mouse_check_button_pressed(mb_right)) {
  var count, ids;
  count = 0;
  for (i = 0; i < instance_number(obj_unit); i += 1) {
    if (instance_find(obj_unit, i).selected == 1) {
      count += 1;
      ids[count] = instance_find(obj_unit, i).id;
    }
  }
  //show_message(count);

  for (i = 0; i < count/4; i += 1) {
    for (j = 0; j < count/4; j += 1) {
      var ii;
      ii = ids[i + j];
      ii.new_x = mouse_x + (i * 20);
      ii.new_y = mouse_y + (j * 20);
    }
  }
}